Primarily, I don't think we're overly focused on the costs. We're focused on the risks that would arise from that increased metadata retention.
Currently, we maintain the minimum amount of data necessary to provide the service. My understanding from the current draft is that it could force an increase beyond that time. What we're looking at then is just a larger amount of data that could be breached by an attacker and used to commit other crimes.
We're not aware of that ever having happened to Apple so far, and I will touch wood, but part of that is because we reduce that threat profile today as much as possible.